The present invention relates to a safety closure specifically designed for water reservoirs used to provide coffee machines with pressurized steam.
It is a known fact that steam pressure coffee machines have a water reservoir for obtaining steam, which is duly connected in industrial coffee machines to the general water supply system but household coffee machines must be filled with water manually, before making coffee, through the relevant mouth leading into such reservoir.
More specifically, when opening the coffee machine reservoir for refilling with water, the procedure is in principle inconvenient since the reservoir's safety closure systems are currently screw stoppers which, on the removal from the coffee machine under operating pressure, might permit a jet of water steam to spurt out, with the risk this represents to the user who may be burnt.
In an attempt to overcome this problem, the applicant has suggested a safety mechanism in his Spanish patent 540,281 and certificate of addition thereof 8700605. The safety mechanism disclosed in the Spanish patent eliminates the above-mentioned risk. More specifically, the solution adopted to such end provides that the water reservoir is equipped with a screw stopper, the periphery of the mouth of which stopper has a plurality of recesses which can house a rod that tends to enter into any of the same urged by the actual pressure inside the reservoir, so that until such pressure falls below a given security level, which is not hazardous, the stopper cannot be removed, and hence the reservoir cannot be opened.
However, two problems have occurred in the afore-discussed safety mechanism, one problem being that it is inconvenient to fill the reservoir, because the stopper must be unscrewed and then screwed again which would involve two slow procedures with the first being frequently more difficult because the stopper connection to the mouth of the reservoir is excessively tight, and the other problem being that failure of the stopper's blocking rod would leave the coffee machine's water reservoir without protection.